The last thing all water and solute molecules pass through before they enter the vascular system of roots and move upward to the leaves is __________.

• A. a stoma
• B. a root hair cell
• C. an epidermal cell
• D. a stele
• E. an endodermal cell

Answer: (E)

Verified step by step guidance

1. Understand the structure of a plant root: The root is composed of several layers, including the epidermis, cortex, endodermis, and the vascular system (stele). Each layer has a specific function in the transport of water and solutes.
2. Identify the role of the endodermis: The endodermis is a single layer of cells that forms a boundary between the cortex and the stele. It is crucial for regulating the flow of water and solutes into the vascular system.
3. Learn about the Casparian strip: The endodermal cells contain a Casparian strip, a band of cell wall material that is impervious to water and solutes. This strip forces water and solutes to pass through the cell membranes of the endodermal cells, allowing selective uptake.
4. Recognize the importance of selective uptake: By passing through the endodermal cells, the plant can control which solutes enter the vascular system, ensuring that only beneficial nutrients are absorbed while harmful substances are excluded.
5. Conclude the pathway: After passing through the endodermal cells, water and solutes enter the stele, where they are transported upward through the xylem to the leaves and other parts of the plant.